Centrifugal pump



Jan'. 9, 1945. G.' P. E. HOWARD 2,366,964

CENTRIFUGAL PUMP Filed May 5, 1942 3 Sheets-Sheet l Arme/wxs Y Jan. 9,1945. c. P. E. HOWARD CNTRIFUGAL PUMP Filed Mays, 1942 3 sheets-sheet 2Jn 9 1945- G, P. E. HOWARD 2,366,964

` CENTRIFUGAL PUMP v Filed May 5, 1942 5 Sheets-Sheet 3 01 [JLlll l l Il l I 14m GJ? How/ARD.

l Patented Jan. 9, 1.945

y 2,366,964 l CEN'rRIFUdArl PUMPl y Giles ,Philip Eliot Howard,Aniersliam',l lilngland Application Mayv 5, 1942, Serial No. 441,842 3In Great` Britain Mayv"5,1941

izr'z'laims.v (arios-1.02)-

, y e I meansy may comprise'- juxtaposed sets `of, spiral This"invention vrelates centrifugalV pumps of the multi-stage" type.v

Pumps of this. kindjhave 'hitherto been built' upxofparts comprising,for each stage, asuc-y tion chamber defining member, an impellermembei'r andfguide meansioradirecting .the liquidv dischargedrfron-ifthelirnpeller into the: suction. chamber of thenext-Ystage. "1nthey case forr instance of ordinary-'- horizontal high lift` turbopumps, eachvstager-comprlises a bowl having pas-1 j sages designedtoconvert' thehigh' speed tan# gentialilow from, oneimpeller into .anaxial flowat'y the;k entryv of` thei next impel1er,-the 'bowls'being"'connectedtogetherfin series; or alterna-- tively,` each stage.`comprises an impeller, afdiffuser member taking the radial andtangentiall ow- @and/converting it? into a tangential and axial iiow;and althirdguide member which convertsthis latteriflow 'into apurelyaxial; flowV at the eye ofthe next impelleri vThis arrangemenf--is esometimes modiiiedso thatthe. diffuser -vanesl do not lchange thedirection of@ i'lo'w'entirely to the axial but merely reduce thetangential .velocity and in this caseV anA outer chamber o fv semiytoroidal form is` provided; to redirect the. iiow intovthemeturn.guideswhich'4 convert the flowA .Lz-

into anv axial iowl at fthefi eye ofthe; next im peller. i

f Inl all such forms of construction yexternal meansv have tof beiprovided; for; assembling; ,the stationaryr or,v guidev members-noi thesuccessive i stages in:end-toendrelationship, and fory this purpose,there: are usuallyy employed yeither i an enveloping` :tubular memberwith compression means atl the ends or long bolts passing outside s orthroughgholes in the-.guide members or studs and nuts-.laia-:each1stage.to bolt it to the next.' In every-fv case, such securingmeansentail a substantialfincrease in the outside diametervof the'`pump, and-anyoutside. casingv provided is extraneous. `Vto the essentialcomponentl parts of thepump. f s

lIl'x-is general mode ofl constructionA is; dictated by the assillned:desirability of"v suppressing turbulence by"` curving.y the outer wall'o-f. tiles-guideA means; :by which the liquidflow is diverted betweenthe point of, leaving an impeller .of one stage and enteringjthe,suction chamberl of the nextstage.v

.I- havey foundtliaffgl ,givenl suitable arrangef ment` and dimensioningofthe. guide means, this assumed;` requirement may beA dispensed ,with,andl that the divertingi peripheraly .surface of thei guide. means, maybenormal to tharadial planes. of..v .thek pump assembly,ywthoutjappiieficialrle loss .of-ediciency.. Consequently the guide orinclinedfvanesmounted in afperipherally openannular'supporting-structure and` adalfxtedv tofguide the dischargingandente'ringl` nows tangentially, while thefdiversion therebetween iseffected by' a cylindrical/wall suitably 'spaced from said sets ofvanes.

From "this it follows lthatv theL provision ofl an independent" housingcanr ber dispensedr with' and the required lcylindrical lWall may beformed" n theA housing itself which thus particilzaatesjinv the liquidguidingfunction. A y

The invention accordinglyjconsists in a multistage centrifugal pumpfwherei'n the. external housing itself forms part-'ofl the meansfor guiding the ilow -betweenfsuccessivestages.

In lfurther development ofthe invention, the stationaryparts of- 'theypumpvv areA formed with cylindrical peripheral surfaces ofthersamediameter and theexternal housing consists of; -a singlecylindrical member' kadapted 'tol be simply 'ttedslidinglyover theconsecutively assembled partsloffthe'pump, to 'complete the assembly;

It will be appreciatedrthat in1thisway, a ver-y reat simplification.` ofthe work of assembly and dismantling is achieved, as compared with pumpshavingi an'l extraneous sectional housing, quite apart fromv thefact'that'fthe construction orf the individual parts is greatlysimplified and the Ytotal amount of machining required is verymaterially 1 reduced.V LOwing-,tothe use of acne-piece cylintobesubstantially, reduced without sacriceof strength. -Moreover, owing tothe economy in diametrical dimensions-,achieved by the invention,A the.furtheradvantage is obtained, that impellers of larger y,diametermayfbezL-used, re-

Esulting in a greater pressure gain per stage and enabling fewer stagesto be used in a pump oi :given .over-all diameter, with fewer parts. anda-shorter shaft. g

InV order that the inventionmay be `moreyfully comprehended. andYreadily carried into. pracftice, an embodimentfor its various featuresisillustrated, by` way of ,example only, inthe accompanying drawings, inwhich:`

Figure 1 shows, inlongitudinal section, a completepump` according VtoVthe invention, with a combined iiuid admission and motor attachmentpiecev tted .to the4 inlet end thereof;

Figures l2, andy` 3show in axialsection yand in elevation respectively,one of the impellers of thelpump; l

Figures 4 andv 5 are viewsralso invaxial section and in elevationrespectively of an interstage guide Vane member;

Figures 6 and '7 are respectively an axial sectional view and anelevation ofthe end bearing member or cap of the pump rotor;

Figures 8 and 9 are like views of the balance disc;

Figures 10 and 11 `are like views of the balance seat; and

Figures 12 and 13 are like views of a diffuser member operative on thefluid on discharge from an impeller,

As shown in'Figure 1 the pump is of multi stage type with threeconventional stages, and the pump is terminated at one end by a fluidadmission rpiece I through which the pumped liquid is admitted to thefirst stage of the pump proper. The said fluid admission piece l isconstru-cted, in accordance with the invention forming the subject;matter or British application No. 5820/41 led May 5, 1941, with a cavity2 which houses the couplings between the pump shaft 4 and the shaft ofthe driving motor,

which is not shown, but is bolted to the end flange of the admissionpiece.

'I'he cavity 2 is formed by a conical wall or socket 6, the forward endof which is bored to form a seating 1a to receive the bearing sleeve 1for the shaft 4, the bearing being cooled by con duction to the wall ,Eand seating 1a andA by the' pumped liquid which sweeps over the outsidesof the seating 1a and wall 6. The heat of the `top motor bearing and theend turns of the motor winding is also transmitted to the wall 6 by theliquid contained in the cavity 2 and maintained in a state of turbulenceand circulation by the rotating coupling 3. Liquid for lubrication ofthe pump bearing can pass along the bearing clearance from cavity 2, andthe end of the bearing is protected` against the entrance of sand or thelike into the bearing by the sand bell 8, which has a number of openings9 to allow adjustment of the pump shaft by means of a tommy bar appliedthrough one of the inlet orifices of the admission piece I. Theadmission piece I is surrounded by a gauze or perforated screen |0 toprevent the entry of solid matter into the pump through the inletorifices and'passages of the admission piece.

On the pump shaft 4 are successively assembled the distance sleeve 4a,the sand bell 8, and the three impellers II each of which comprises anelongated or sleeve-like hub I2 carrying the impeller wheel properformed by a solid wall or flange I3 and an annular Wall I4 which leavesan opening round the hub sleeve AI2 to form an annular inlet eye I5.Between the Walls I3 and I4 are disposed vanes I6 suitably designed toproduce the desired flow of the liquid through the impeller.

Between the impellers are disposed stationary return guide vane membersI1, carrying wearing rings I8 of the kind forming the subject matter ofBritish Letters Patent No. 539,373. The return guide vane members I1,comprise a disc wall |1 of less diameter than the end ring of theadmission piece I, having a short hub I9 fitting on the subsequentimpeller hub sleeve I2, guide vanes 20, and an annular wall 2| of thesame diameter as the end ring of the admission piece l, Whose internalperiphery forms a throat 22 opening into the eye of the next impellerII.

The wearing ring I8 is carried by the annular wall 2| and makes runningcontact with a shoulder ring on the internal periphery of the annularwall I4 of the adjacent impeller II, and between the periphery of thedisc Walls I1 of the return guide vane members I1, and the wearing ringsI8 of the preceding guide vane member I1 are clamped diffuser memberscomprising suitably curved vanes 23, surrounding the impeller II,projecting laterally from annular plates or rings 24 (Figures 12 andlS)Packing rings 33 are disposed between the diffuser rings 24 and theperipheries of the'annular walls 2| of the return guide vane members I1.The vanes 23 do not extend as far as the periphery of the ring 24, whichcorresponds in diameter to the rings 2l and the end ring of theadmission piece I, so that an annular space surrounds the vanes 23 whichis bounded by the outer casing of the pump, the surface of which thusparticipates in the guidance of the water flow between stages..

Above the final stage `impeller I l and abutting against the vanes 23 ofthe last diffuser member, is disposed an annular balance seat 25carrying a balance ring 23, which makes contact with a wearing ring 21carried by a balance disc 23 mounted on the shaft 4. The balance disc 28has an elongated sleeve 48 keyed on shaft 4. The parts keyed to shaft 4viz: distance sleeve 4a., sand bell 8, impeller hub sleeves I2, andbalance disc hub sleeve 43, are axially clamped on shaft 4 by the endnut 29, and finally the sleeve 43 on shaft 4 is fitted into the end cap38, which contains the topV bearing sleeve 49, held in bearing shell 50,and in its cavity accommodates the balance disc 28. The end cap 30 isformed integral with the upper end member or delivery piece 3| of thepump, being connected thereto by webs 44 so as to form delivery channelssweeping overr the outer surface of the cap 39, and communicating on theone hand with the discharge opening 32 of the pump and with the annularperipheral space surrounding the diffuser 23, 24 encircling the lastimpeller I I on the other hand.

Surrounding the delivery piece 3| is a bolster ring 34 with aninterposed packing ring 35, and the whole of the parts assembled on theshaft 4, including not only those keyed to the shaft, but also theinterposed annular members, viz: balance seat l25, impellers II,diffuser members 23, 24, and return vane members I1 with their wearingrings I8, are inserted, as a cylindrical block, into a plain cylindricalcasing 36, which tsv on, and is fastened to the periphery of the endring of the admission piece I by grub screws 31. The annular interposedmembers of the pump as sembly are then tightened up by means of thrustbolts 38 threaded in a counter `supporting ring 39 inserted in thedischarge end of casing 35 and secured by grub screws 42|.` Finally aflanged ring 4| carrying the delivery pipe 42 is secured over thedelivery piece 3| of the pump by means of the nuts 43 on bolts 38. y

From the foregoing description'it will be appreciated that when thebolster ring 34 is tightened up by the thrust bolts 38, the deliverypiece 3|, and end cap 38, together with the diffuser members 23, 24,wearing plates I8, return vane members I1, and admission piece I, form asolid cylindrical assembly presenting a smooth cylindrical outer wallfitting ywithin the cylindrical outer casing 35. Dismantling is effectedsimply by reversing the assembly operations.

It will be understood that the spaces formed between 4the inner Wall ofthe casing member 35 and the outer edges of the vanes 23 and the annularplates 24 of the diffuser members constitute of the, guide vanas `A23V`detriment-al' turbulence inthese chambers-is avoided:

The invention thus provides a centrifugal pump with a one-piece outercasing which serves the dual purposes of guiding the pumped liquid 4froma set of diffuser vanes to a set of return vanes and of acting as themain locating means for the pump assembly. It also provides a pump whichis simple and robustr in construction, of light weight and requiring aminimum of machining, and which is capable of being assembled anddismantled with exceptional ease and rapidity.

What I claim and desire to secure by Letters Patent is: Y

1. A multi-stage, radial flow centrifugal pump comprising a plurality ofbladed impellers arranged in coaxial stages and respectively cooperatingwith adjacent bladed guide members for controlling the ow betweenstages, in combination with a one-piece casing surrounding the impellersand guide members in radially spaced relation thereto and providing acylindrical sur- -face defining within the same circumferential channelsoutwardly of the guide 'members for guiding the flow from an impellerinto the adjacent guide member as thepumped uid passes from one impellerto the next.

2. A multi-stage, radial flow centrifugal pump comprising a plurality ofimpellers arranged in stages in coaxial relation, and associated guidemembers for controlling the flow of liquid beripheryA yofi-the finalimpellernchamber, .andfa bearing for onewendof thepum-p shaft,supportedv by the-bearingfshell.

16. A- .pumpas'deiinedin claim 3.,'wl1ereinA the set' of diffuser vanes:has an` annular form, with? v.the variesv disposed about `the' periphery-of* the; impeller 15o-guide the liquidin a radially -outwardfdirection, and the cylindrical wall of the outer external one-piececylindrical casing circumfertween said stages, said impellers and guidememf bers being threaded in succession upon a central shaft and enclosedby a one-piece cylindrical casing, and the guide members including meansfor directing the flow in directions both radially and outwardly andradially inwardly in succes'- sionbetween the impellers of successivestages.

3. A centrifugal pump comprising a rotary bladed impeller to produceradially outwardl flow respecting the axis of rotation, a set ofstationary diffuser vanes adjacent to the impeller and in the path ofradial flow from the latter, a set of stationary radially inward flowreturn vanes also associated with said impeller and diffuser vanes inaxially spaced yrelation thereto and coaxial therewith, and a one-piececylindrical casing en nels leading to a central opening registering withthe eye of the first impeller, a bearing shell disposed in said endmember in such manner thatA the outside of the 'bearing shell is sweptbythev fluid passing along said channels, and a bearing for one end of thepump shaft, mounted in said bearing shell. y

5. A centrifugal pump as defined in claim 2,

' including an end member in one end of thecasing provided with an axialuid discharge open-y ing, a bearing shell disposed in said end member sothat its outside wan is swept by the fluid passing to said dischargeopening fromfthe peentially spaced from the impellers, and into whichthe vcylindrical shaft assembly is axially inserted and fastened at itsends, and means for axially clamping the intermediate annularfluid-guiding partsV to hold the same stationary while leaving theimpellers free to rotate relative thereto.

8. A centrifugal pump as denedin claim 2, in

combination with an end member disposed at one endof the casing andprovided with fluid inlet orifices and channels leading to a centralopening registering with the eye of the rst impeller, said end memberserving not only as an admission piece for the pumped fluid, but also asa connecting piece between the pump and motor casings.

9. A multi-stage, radial ow centrifugal pump including, in combination,a plurality of radially outwardly discharging impeller members arrangedin consecutive stages on a common axis, radially outwardly directing andradially inwardly directing bladed guide members between consecutivestages, and an outer one-piece cylindrical casing radially outwardlyspaced from the impellers and .providing an interior cylindrical surfacefor converting the radially outward flow of the fiuid from an impellerand its associated outwardly directing guide member into the adjacentinwardly directing guide member.

10. A multi-stage, radial flow centrifugal pump including, incombination,A a shaft, a plurality 5 of impeller members mounted insuccession on said shaft, a plurality of stationary radially outwardlyand inwardly directing guide vane 111cm-,

back-to-back abutting relation to eachother between each pair ofimpeller members, and a casing enclosing the impeller members and vanemembers and providing cylindrical fluid-guiding surfaces concentric withthe pump shaft between said diiiuser and 'return vane members to directthe liquid flow from the diffuser vane members to the return vanemembers .consecutively be tween the impeller stages.

12. A multi-stage, radial oW centrifugal pump including, in combination,a shaft, a plurality of impeller members mounted in succession on saidshaft, a plurality of annular return vane members respectively locatedbetween said impeller members, hubs on said impeller members located inand by said annular return vane members, an-

nular diffuser vane members also respectively located between saidimpeller members and displaced axially from said return vane members inabutting relation thereto, and a, one-piece cylindrical casing fittingthe external peripheries of said diiuser and return vane members.

GILES P. E. HOWARD.

